1. Field of the Invention
The present invention relates to a bag or container of the type having a sealed flap and folded closing one end of the container with the seal adjacent one end of the flap fold of a reduced bonding strength to facilitate opening the bag, while maintaining a seal prior to opening, provided with a handle formed along the sealed and folded flap to facilitate carrying the bag.
More particularly, the present invention relates to a bag having a flap hingedly coupled at one end of the bag and sealed to one of the bag panels with a portion of the seal adjacent one bag corner having a reduced adhesive bonding strength to facilitate opening of the bag at the flap corner. Additionally, the invention relates to the formation of a handle on the bag by refolding the sealed flap and adjacent bag panel along a lower foldline and tacking the refolded flap to the adjacent bag panel inwardly from the fold ends to form a finger grip therebetween.
2. Description of the Prior Art
Containers or bags formed of heavy weight, multiple ply paper are conventionally employed for containing, storing and shipping flowable, fine powdery materials and small sized granular products, such as starch, food products, chemicals, cement and the like. The flowable nature of these products permit the bags to be filled by inserting a filler spout of a dispensing machine into an opening of the bag and delivering the product from a source through the spout into the bag. The bag construction and filling apparatus for filling bag in this manner are disclosed in U.S. Pat. No. 4,316,574 to Lepisto, which patent is hereby incorporated by reference.
One problem which has plagued bags of this type is the provision of a simple and neat way to open the bags without using tools. Often heavy weight bags have no provision to facilitate opening and require the use of a sharp instrument to cut an opening in the bag. Such opening procedure is inconvenient and dangerous. Additionally, opening the bag using a sharp instrument often results in tearing of the bag preventing proper resealing for storing any remaining bag contents and preventing controlled dispensing of the contents.
Hand opening of heavyweight bags sealed with hot melt adhesive is extremely difficult due to the strength of the bag material and the seal. Force applied to the closing flap will tear the bag since the bond between the adhesive and paper is stronger than the paper itself. Thus, hand opening of such bags is difficult, forms a poor dispensing spout, causes spilling of the contents, and prevents resealing of the bag.
Special mechanisms for opening bags have involved the use of strings, e.g., U.S. Pat. No. 2,203,924 to Pletscher and U.S. Pat. No. 2,151,523 to Orr, the inclusion of a glued tab, e.g. U.S. Pat. No. 3,081,930 to Owens and the use of tape, e.g., U.S. patent application Ser. No. 243,829, filed Mar. 16, 1981, entitled "Easy Open Valve Bag".
The previously tried closure opening mechanisms have suffered from numerous deficiencies, including a high failure rate difficult and expensive manufacturing, adverse effects on the sealing of the bag and difficult operation. The string often fails by becoming loose from the bag without tearing the bag material and is difficult and expensive to install due to the precise gluing necessary. The thick material of the bag often makes the tab and tape mechanisms difficult to open. Additionally, such opening mechanisms provide a relatively large opening making controlled dispensing of the contents and resealing of the bag difficult.
Thus, previous systems for opening heavyweight bags for powder and granular substances have not been effective since they are difficult and expensive to manufacture, have a high failure rate, are difficult to operate and do not form a neat pouring spout for accurately dispensing the bag contents. Additionally, these systems make it extremely difficult or impossible to reseal the bag to properly store any unused contents in the bag.
It has now been discovered and disclosed in the copending related applications identified above, that the disadvantages associated with conventional systems for opening containers closed by a sealed flap can be eliminated by a container seal extending the entire width of the flap and including first and second portions longitudinally spaced along the seal with the first portion having a bond strength significantly less than that of the second portion. The container has a body portion, an opening in the body portion providing access to the container interior, and a fold over flap for extending over and closing the opening. The flap is attachable to the body portion by the seal extending adjacent to and generally along the opening.
In this manner, the flap at the first portion of the seal can be easily separated from the body portion to facilitate opening the container, while forming an adequate seal at the first portion prior to opening. Additionally, containers formed with seals according to the present invention are simple and inexpensive to manufacture, have a low failure rate, form neat pouring spouts for accurate dispensing and are resealable. The treatment of the seal first portion can be accomplished simply and quickly without adding hardware to the bag itself or substantially modifying the container forming machinery.
Preferably, the container is in the form of a bag having a plurality of panels hingedly coupled along fold lines, an opening on one end of the bag, and a flap hingedly coupled to one of the panels along a fold line for overlapping a portion of an opposite panel and closing the opening. A hot melt adhesive layer extends across the entire width of the flap for adhering the flap to the opposite panel and sealing the opening. The adhesive bonding strength of a first portion of the hot melt adhesive layer is reduced by providing a spot coating of abherent (abhesive) comprising kaolin clay on the opposite panel portion corresponding to the first portion of the adhesive layer. When the flap is folded and sealed in the conventional manner, the spot coating of abherent reduces, without eliminating, the adhesive bond strength of the seal between the flap and opposite panel at the first portion adjacent one corner of the bag to permit the flap to be easily separated from the opposite panel portion. At the seal first portion, separation occurs between the spot coating and the bag panel, rather than at an interface with the hot melt adhesive.
A line of perforations can be formed in the flap extending from the juncture of the adhesive layer first portion and the remainder of the adhesive layer to the flap fold line. This permits the multiple plies of paper forming the bag and the flap to be easily separated in a neat and simple manner providing a pouring spout from which the bag contents can be accurately dispensed. The first portion can be located adjacent the corner of the bag opposite the filling valve means such that the formation of the easy opening system does not interfere with the formation and operation of the filling mechanism.
The spot coating can be printed, sprayed or brushed on the bag during its manufacture. In this manner, the reduced bond strength of the seal first portion is automatically formed during the conventional bag sealing process.
The type of bag described is used for cement, dog food, fertilizer, bird seed, etc., which is heavy, usually in the 15-30 lb. range. For these uses, a handle on the bag would be a great convenience.
A primary problem in designing a handle for a bag of the type described, is the method of attaching it to the bag. The outside ply of the bag is not strong enough to resist a rapid or uneven application of force so that patching a handle to the bag is not practical. The preferred method is to design a handle that will distribute the applied forces over as large an area as possible, concentrate it in the thickest (largest number of plies) area and if possible construct it so it is an integral part of the bag itself, e.g. not an attachment or appendage.
A second problem is that although the bag provided with a handle will have a certain added sales appeal, the increase in monetary value will not be great enough to justify complicated additional equipment or expensive materials for the provision and/or formation of the handle.